SDS-PAGE and Western blot analysis of purified HRPII. (A) SDS-PAGE. Recombinant HRPII (0.5 μg) was treated with 5% 2-mercaptoethanol and run on 12% SDS-PAGE. The gel was stained with Coomassie brilliant blue. (B) Western blot. Recombinant HRPII (10 ng) and native HRPII (20 ng) were run on SDS-PAGE as in panel A, except that a 10% to 20% gradient gel was used. The gel was blotted onto a nitrocellulose membrane and probed with a monoclonal antibody to HRPII (mAB2G12) as described in “SDS-PAGE and Western blot.” (A-B) Molecular mass markers are listed on the left. rHRPII indicates recombinant HRPII; and nHRPII, native HRPII.